till Jan. 24, 1836. He says that the alteration of form which had taken place between the beginning of November and this date, during which interval the comet had been lost in the Sun's rays, was "remarkable", and he goes on as follows:—
"Jan. 24. To the naked eye it was as bright as a star of the 2.3 or 3rd magnitude: there was no tail. In the 14-feet reflector, it presented an opaque, circular, planetary disc, tolerably well defined, encompassed by a delicately bright coma or halo, which was likewise circular.
"Crossing the disc in a direction not deviating much from parallelism with the equator, appeared an oblong, elliptical body, distinguished from the rest of the disc by its superior whiteness, and a semblance of greater density. The diameter of the disc measured 2' 11"; of the coma, 8' 12".
"On the 25th, the circularity of the preceding limb of the cometary disc was partially broken, its dimensions were increased, the elongated portion was better marked, and its following end was brighter than the preceding.
"On the 26th, the halo had diminished, and the dimensions of the disc, or body, as it should now be called, were further increased. A spot like a nucleus could be occasionally seen in the brighter end of the oblong portion.
"On the 28th, the halo or coma had vanished. The nucleus was distinct, like a faint small star in the following end of the oblong portion. The dimensions of the body had greatly increased, while the intensity of its light had proportionately diminished. The general outline of the cometary body seemed approximating to a parabolic curve, the preceding end of which might be represented by conceiving the tail, as seen before the perihelion passage, abruptly separated from the head, leaving a serrated or ragged outline. The oblong portion with the nucleus resembled a small comet inclosed in the body of a larger one.
"On the 30th, the body was rather more elongated. A line drawn transversely through the nucleus measured 11' 42", being 5 times the diameter on the 24th; or 29 times the area of a circle of which 2' 11" is the diameter. But the visible area of the whole body on the 30th could not be less than 35 times that of the 24th, excluding the halo. The nucleus was nearer to the S. than to the N. side by 32".
"Throughout the succeeding three months the coma went on increasing, until the outline finally became so faint as to be lost in the surrounding darkness, leaving a blind, nebulous blotch with a bright centre enveloping the nucleus of variable brightness, depending on moonlight or the state of the atmosphere, and variable distance."[1]The physical appearance of Halley's Comet at the 1835 apparition seems to have been in many respects very remarkable, and, did the statements made not emanate from some of the most distinguished astronomers of the time, it might be permissible to distrust them. It is impossible, however, to
- ↑ Mem. R.A.S., vol. x, p. 92. 1837.
